snprintf支持格式化结构体

demo/test_handle_logger.c

@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
+#include <string.h>
 
 void *sample_handle = NULL;
 void *test_handle = NULL;
@@ -19,9 +20,25 @@ int g_thread_num = 0;
 const char *g_zlog_conf = NULL;
 volatile long g_start_time = 0;
 volatile long g_end_time = 0;
+struct test_A{
+	int a;
+	char *str;
+	long long b;
+};
+int MESA_fmt_handler_A(void *info, char *buf, int maxlen)
+{
+	struct test_A *obj = (struct test_A *)info;
+	int n = snprintf(buf, maxlen, "a=%d,s=%s,b=%lld", obj->a, obj->str, obj->b);
+	return n < maxlen?n:maxlen - 1;
+}
 
 void call_logger(int log_num, int thread_num)
 {
+	
+	struct test_A a;
+	a.a = 10;
+	a.str = "hello";
+	a.b = 123456;
 	int i = 0;
 	struct timespec start, end;
 	long start_time, end_time, time_cost;
@@ -40,12 +57,13 @@ void call_logger(int log_num, int thread_num)
 	}	
 	for(i = 0; i < log_num; i++)
 	{
-				MESA_handle_runtime_log(sample_handle, RLOG_LV_DEBUG, "sample", "sample_handle MESA_handle_runtime_log, i = %d, thread_num = %d", i, thread_num);
+		//MESA_handle_runtime_log(sample_handle, RLOG_LV_DEBUG, "sample", "sample_handle MESA_handle_runtime_log, i = %d, thread_num = %d", i, thread_num);
 		//sleep(1);
-				MESA_handle_runtime_log(test_handle, RLOG_LV_INFO, "test", "test_handle MESA_handle_runtime_log, i = %d, thread_num = %d", i, thread_num);
+		//MESA_handle_runtime_log(test_handle, RLOG_LV_INFO, "test", "test_handle MESA_handle_runtime_log, i = %d, thread_num = %d", i, thread_num);
-				//MESA_HANDLE_RUNTIME_LOG(sample_handle, RLOG_LV_FATAL, "sample", "sample_handle RUNTIEM_LOG test, i = %d, thread_num = %d", i, thread_num);
+		MESA_HANDLE_RUNTIME_LOG(sample_handle, RLOG_LV_FATAL, "sample", "sample_handle RUNTIEM_LOG test, i = %d, thread_num = %d", i, thread_num);
 		//sleep(1);
-				//MESA_HANDLE_RUNTIME_LOG(test_handle, RLOG_LV_FATAL, "test", "test_handle RUNTIEM_LOG test, i = %d, thread_num = %d", i, thread_num);
+		MESA_HANDLE_RUNTIME_LOG(test_handle, RLOG_LV_FATAL, "test", "test_handle RUNTIEM_LOG test, i = %d, thread_num = %d", i, thread_num);
+		MESA_HANDLE_RUNTIME_LOG(sample_handle, RLOG_LV_FATAL, "sample", "sample_handle RUNTIEM_LOG test, i = %d, thread_num = %d,struct a =%A", i, thread_num, &a);
 	}
 	clock_gettime(CLOCK_MONOTONIC, &end);
 	end_time = end.tv_sec*1000000 + end.tv_nsec/1000;
@@ -130,6 +148,10 @@ int main(int argc, char ** args)
 		printf("get log sample_handle error\n");
 		return -1;
 	}
+	if(MESA_handle_fmt_rule_register(sample_handle, 'A', MESA_fmt_handler_A, 512) < 0){
+		printf("struct a register error\n");
+		return 0;
+	}
 
 	test_handle = MESA_create_runtime_log_handle("./log/test_log", RLOG_LV_DEBUG);
 	if(test_handle == NULL)

inc/MESA_handle_logger.h

@@ -14,6 +14,19 @@ extern "C"
 {
 #endif
 
+#include <pthread.h>
+
+#define MESA_PTHREAD_CACHE_BUF_DEFAULT_LEN      1024
+#define MESA_PTHREAD_FMT_BUF_DEFAULT_LEN      256
+extern pthread_key_t MESA_pthread_key;
+void MESA_pthread_free_handler(void *arg);
+
+typedef int (*MESA_fmt_handler)(void *info, char *buf, int buflen);
+int MESA_handle_fmt_rule_register(void *handle, char sign, MESA_fmt_handler handler, int buflen);
+int MESA_handle_check_fmt_sign(void *handle, char sign, MESA_fmt_handler *handler, char **buf, int *maxlen);
+void MESA_free_pthread_private(void *arg);
+
+
 #define RLOG_LV_DEBUG       10
 #define RLOG_LV_INFO        20
 #define RLOG_LV_FATAL       30
@@ -21,7 +34,7 @@ extern "C"
 
 int MESA_handle_runtime_log_creation(const char *conf_path);
 int MESA_handle_runtime_log_reconstruction(const char *conf_path);
-void MESA_handle_runtime_log_destruction();
+void MESA_handle_runtime_log_destruction(void);
 
 #define MESA_HANDLE_RUNTIME_LOG(handle, lv, mod, fmt, args...)   \
     MESA_handle_runtime_log((handle), (lv), (mod), "file %s, line %d, " fmt, \

inc/snprintf.h

@@ -0,0 +1,24 @@
+#ifndef _PORTABLE_SNPRINTF_H_
+#define _PORTABLE_SNPRINTF_H_
+
+#define PORTABLE_SNPRINTF_VERSION_MAJOR 2
+#define PORTABLE_SNPRINTF_VERSION_MINOR 2
+
+#ifdef HAVE_SNPRINTF
+#include <stdio.h>
+#else
+extern int snprintf(char *, size_t, const char *, /*args*/ ...);
+extern int vsnprintf(char *, size_t, const char *, va_list);
+#endif
+
+#if defined(HAVE_SNPRINTF) && defined(PREFER_PORTABLE_SNPRINTF)
+extern int portable_snprintf(void * handle, char *str, size_t str_m, const char *fmt, /*args*/ ...);
+extern int portable_vsnprintf(void *handle, char *str, size_t str_m, const char *fmt, va_list ap);
+/*#define snprintf  portable_snprintf*/    /*others use libc snprintf*/
+/*#define vsnprintf portable_vsnprintf*/
+#endif
+extern int asprintf  (void * handle, char **ptr, const char *fmt, /*args*/ ...);
+extern int vasprintf (void * handle, char **ptr, const char *fmt, va_list ap);
+extern int asnprintf (void * handle, char **ptr, size_t str_m, const char *fmt, /*args*/ ...);
+extern int vasnprintf(void * handle, char **ptr, size_t str_m, const char *fmt, va_list ap);
+#endif

src/MESA_handle_logger.c

@@ -1,6 +1,9 @@
 #include "MESA_handle_logger.h"
+#include "snprintf.h"
 #include "zlog.h"
-
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <ctype.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -14,12 +17,30 @@ static int g_zlog_conf_fp = -1;
 static char global_conf_filepath[MAX_HANDLE_LOG_PATH] = "";
 static char tmp_conf_filepath[MAX_HANDLE_LOG_PATH] = "";
 
+#define MESA_FORMAT_RULE_MAX  16
+pthread_key_t MESA_pthread_key;
+pthread_once_t MESA_pthread_key_once = PTHREAD_ONCE_INIT;
+
+struct MESA_pthread_private{
+	char *fmt_buf;
+	char *cache_buf;
+	int fmt_buf_len;
+	int cache_buf_len;
+};
+struct MESA_fmt_obj{
+	char sign;
+	MESA_fmt_handler handler;
+};
+
 typedef struct log_handle_t
 {
     int runtime_log_level;
+	int fmt_rule_num;
     zlog_category_t *zc;
     const char *global_conf_path;
     char runtime_log_file[MAX_HANDLE_LOG_PATH];
+	int fmt_buf_len;
+	struct MESA_fmt_obj fmt_rule[MESA_FORMAT_RULE_MAX];
 } log_handle_t;
 
 
@@ -127,6 +148,7 @@ static const char *loglevel_to_name(int level)
 
 static void snapshot_handle_info(const char *handle_name, const char *log_path, int level)
 {
+	int n = 0;
     char zlog_rule_conf_content[MAX_HANDLE_LOG_PATH + 1] = "";
     static char *tmp_prefix = "/tmp/MESA_handle_logger/";
     static char *zlog_conf_init_buff = "[global]\ndefault format = \"%d(%c), %V, %F, %U, %m%n\" \n[levels]\nDEBUG=10\nINFO=20\nFATAL=30\n[rules]";
@@ -145,13 +167,22 @@ static void snapshot_handle_info(const char *handle_name, const char *log_path,
         {
             return;
         }
-        write(g_zlog_conf_fp, zlog_conf_init_buff, strlen(zlog_conf_init_buff));
+        n = write(g_zlog_conf_fp, zlog_conf_init_buff, strlen(zlog_conf_init_buff));
+		if(n < 0){
+			fprintf(stderr,"write g_zlog_conf_fp error, func=%s, line=%d\n",__FUNCTION__, __LINE__);
+		}
         fsync(g_zlog_conf_fp);
     }
-    snprintf(zlog_rule_conf_content, sizeof(zlog_rule_conf_content),
+    n = snprintf(zlog_rule_conf_content, sizeof(zlog_rule_conf_content),
              "\n%s.%s    \"%s.%%d(%%F)\"",
              handle_name, loglevel_to_name(level), log_path);
-    write(g_zlog_conf_fp, zlog_rule_conf_content, strlen(zlog_rule_conf_content));
+	if(n > 0){
+		n = write(g_zlog_conf_fp, zlog_rule_conf_content, strlen(zlog_rule_conf_content));
+		if(n < 0){
+			fprintf(stderr,"write g_zlog_conf_fp error, func=%s, line=%d\n",__FUNCTION__, __LINE__);
+		}
+	}
+
     fsync(g_zlog_conf_fp);
 
     if(g_zlog_inited == 0)
@@ -162,15 +193,70 @@ static void snapshot_handle_info(const char *handle_name, const char *log_path,
     }
     return;
 }
+struct MESA_pthread_private *MESA_create_pthread_private(void *handle)
+{
+
+	log_handle_t *p_handle = (log_handle_t *)handle;
+	struct MESA_pthread_private *pri = malloc(sizeof(struct MESA_pthread_private));
+	if(pri == NULL){
+		return NULL;
+	}
+	memset(pri, 0 ,sizeof(struct MESA_pthread_private));
+	pri->fmt_buf = malloc(p_handle->fmt_buf_len);
+	if(pri->fmt_buf == NULL){
+		goto error;
+	}
+	pri->fmt_buf_len = p_handle->fmt_buf_len;
+	pri->cache_buf_len = MESA_PTHREAD_CACHE_BUF_DEFAULT_LEN;
+	pri->cache_buf = malloc(pri->cache_buf_len);
+	if(pri->cache_buf == NULL){
+		goto error;
+	}
+	return pri;
+	
+error:
+	if(pri->fmt_buf){
+		free(pri->fmt_buf);
+	}
+	if(pri->cache_buf){
+		free(pri->cache_buf);
+	}
+	if(pri){
+		free(pri);
+	}
+	return NULL;
+	
+}
+void MESA_free_pthread_private(void *arg)
+{
+	struct MESA_pthread_private *pri = (struct MESA_pthread_private *)arg;
+	if(pri == NULL){
+		return ;
+	}
+	if(pri->fmt_buf){
+		free(pri->fmt_buf);
+	}
+	if(pri->cache_buf){
+		free(pri->cache_buf);
+	}
+	if(pri){
+		free(pri);
+	}
+	return ;
+}
+
+void MESA_alloc_pthread_key()
+{
+	pthread_key_create(&MESA_pthread_key, MESA_free_pthread_private);
+	return ;
+}
 
 void *MESA_create_runtime_log_handle(const char *file_path, int level)
 {
 	if(file_path == NULL)
 		return NULL;
 
-    int rc = -1;
     zlog_category_t *zc = NULL;
-    FILE *fp  = NULL;
     log_handle_t *p_handle = NULL;
 
     char handle_name[MAX_HANDLE_LOG_PATH];
@@ -199,6 +285,8 @@ void *MESA_create_runtime_log_handle(const char *file_path, int level)
     strncpy(p_handle->runtime_log_file, file_path, sizeof(p_handle->runtime_log_file) - 1);
     p_handle->runtime_log_level = level;
     p_handle->zc = zc;
+	p_handle->fmt_buf_len = MESA_PTHREAD_FMT_BUF_DEFAULT_LEN;
+	pthread_once(&MESA_pthread_key_once, MESA_alloc_pthread_key);
     return (void *)p_handle;
 }
 
@@ -224,9 +312,31 @@ void MESA_handle_runtime_log(void *handle, int level, const char *module, const
     if(p_handle->zc == NULL)return;
 
     va_list ap;
+	va_list ap_bk;
     va_start(ap, fmt);
-    vzlog(p_handle->zc, p_handle->runtime_log_file, strlen(p_handle->runtime_log_file), module, strlen(module), __LINE__, level, fmt, ap);
+	struct MESA_pthread_private *pri = (struct MESA_pthread_private *)pthread_getspecific(MESA_pthread_key);
+	if(pri == NULL){
+		pri = MESA_create_pthread_private(handle);
+		if(pri == NULL){
+			return ;
+		}
+		pthread_setspecific(MESA_pthread_key,(void*)pri);
+	}
+	va_copy(ap_bk, ap);
+	int n = portable_vsnprintf(handle, pri->cache_buf, pri->cache_buf_len, fmt, ap_bk);
+	if(n >= pri->cache_buf_len){
+		char *p = realloc(pri->cache_buf, n + 1);
+		if(p != NULL){
+			pri->cache_buf_len = n + 1;
+			pri->cache_buf = p;
+			va_copy(ap_bk, ap);
+			portable_vsnprintf(handle, pri->cache_buf, pri->cache_buf_len, fmt, ap_bk);
+		}		
+	}
+	
 	va_end(ap);
+	va_end(ap_bk);
+	zlog(p_handle->zc, p_handle->runtime_log_file, strlen(p_handle->runtime_log_file), module, strlen(module), __LINE__, level, "%s", pri->cache_buf);
     return ;
 }
 
@@ -328,3 +438,51 @@ void MESA_handle_runtime_log_destruction()
         close(g_zlog_conf_fp);
     }
 }
+
+int MESA_handle_fmt_rule_register(void *handle, char sign, MESA_fmt_handler handler, int buflen)
+{
+	log_handle_t *p_handle = (log_handle_t *)handle;
+	int fmt_rule_num = p_handle->fmt_rule_num;
+	if(fmt_rule_num >= MESA_FORMAT_RULE_MAX){
+		return -1;
+	}
+	p_handle->fmt_rule[fmt_rule_num].sign = sign;
+	p_handle->fmt_rule[fmt_rule_num].handler = handler;
+	p_handle->fmt_rule_num++;
+	if(buflen > 0 && buflen > p_handle->fmt_buf_len){
+		p_handle->fmt_buf_len = buflen;
+	}
+	return 0;
+}
+int MESA_handle_check_fmt_sign(void *handle, char sign, MESA_fmt_handler *handler, char**buf, int *maxlen)
+{
+	if(!handle || !handler){
+		return 0;
+	}
+	struct MESA_pthread_private *pthread_pri = NULL;
+	log_handle_t *p_handle = (log_handle_t *)handle;
+	int fmt_rule_num = p_handle->fmt_rule_num;
+	int i = 0;
+	for(i = 0; i < fmt_rule_num; i++){
+		if(p_handle->fmt_rule[i].sign == sign){
+			pthread_pri = (struct MESA_pthread_private *)pthread_getspecific(MESA_pthread_key);
+			if(pthread_pri == NULL){
+				return 0;
+			}
+			*handler = p_handle->fmt_rule[i].handler;
+			if(p_handle->fmt_buf_len > pthread_pri->fmt_buf_len){
+				char *p = realloc(pthread_pri->fmt_buf, p_handle->fmt_buf_len);
+				if(p != NULL){
+					pthread_pri->fmt_buf = p;
+					pthread_pri->fmt_buf_len = p_handle->fmt_buf_len;					
+				}
+			}
+			*buf = pthread_pri->fmt_buf;
+			*maxlen = pthread_pri->fmt_buf_len;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+

src/portable_snprintf/LICENSE.txt

@@ -0,0 +1,121 @@
+The Frontier Artistic License Version 1.0
+Derived from the Artistic License at OpenSource.org.
+Submitted to OpenSource.org for Open Source Initiative certification.
+   
+Preamble
+
+The intent of this document is to state the conditions under which a
+Package may be copied, such that the Copyright Holder maintains some
+semblance of artistic control over the development of the package,
+while giving the users of the package the right to use and distribute
+the Package in a more-or-less customary fashion, plus the right to
+make reasonable modifications.
+   
+Definitions
+
+  "Package" refers to the script, suite, file, or collection of
+  scripts, suites, and/or files distributed by the Copyright Holder,
+  and to derivatives of that Package created through textual modification.
+
+  "Standard Version" refers to such a Package if it has not been
+  modified, or has been modified in accordance with the wishes of
+  the Copyright Holder.
+
+  "Copyright Holder" is whoever is named in the copyright statement
+  or statements for the package.
+
+  "You" is you, if you're thinking about copying or distributing
+  this Package.
+
+  "Reasonable copying fee" is whatever you can justify on the basis
+  of media cost, duplication charges, time of people involved, and
+  so on. (You will not be required to justify it to the Copyright
+  Holder, but only to the computing community at large as a market
+  that must bear the fee.)
+
+  "Freely Available" means that no fee is charged for the item
+  itself, though there may be fees involved in handling the item.
+  It also means that recipients of the item may redistribute it under
+  the same conditions they received it.
+       
+
+Terms
+
+1. You may make and give away verbatim copies of the source form of
+the Standard Version of this Package without restriction, provided
+that you duplicate all of the original copyright notices and
+associated disclaimers.
+   
+2. You may apply bug fixes, portability fixes, and other modifications
+derived from the Public Domain or from the Copyright Holder. A Package
+modified in such a way shall still be considered the Standard Version.
+   
+3. You may otherwise modify your copy of this Package in any way,
+provided that you insert a prominent notice in each changed script,
+suite, or file stating how and when you changed that script, suite,
+or file, and provided that you do at least ONE of the following:
+   
+  a) Use the modified Package only within your corporation or
+  organization, or retain the modified Package solely for personal use.
+     
+  b) Place your modifications in the Public Domain or otherwise make
+  them Freely Available, such as by posting said modifications to Usenet
+  or an equivalent medium, or placing the modifications on a major archive
+  site such as ftp.uu.net, or by allowing the Copyright Holder to include
+  your modifications in the Standard Version of the Package.
+     
+  c) Rename any non-standard executables so the names do not conflict
+  with standard executables, which must also be provided, and provide
+  a separate manual page (or equivalent) for each non-standard executable
+  that clearly documents how it differs from the Standard Version.
+     
+  d) Make other distribution arrangements with the Copyright Holder.
+     
+4. You may distribute the programs of this Package in object code or
+executable form, provided that you do at least ONE of the following:
+   
+  a) Distribute a Standard Version of the executables and library
+  files, together with instructions (in the manual page or
+  equivalent) on where to get the Standard Version.
+     
+  b) Accompany the distribution with the machine-readable source of
+  the Package with your modifications.
+     
+  c) Accompany any non-standard executables with their corresponding
+  Standard Version executables, give the non-standard executables
+  non-standard names, and clearly document the differences in manual
+  pages (or equivalent), together with instructions on where to get
+  the Standard Version.
+     
+  d) Make other distribution arrangements with the Copyright Holder.
+     
+5. You may charge a reasonable copying fee for any distribution of
+this Package. You may charge any fee you choose for support of this
+Package. You may not charge a fee for this Package itself. However,
+you may distribute this Package in aggregate with other (possibly
+commercial) programs as part of a larger (possibly commercial)
+software distribution provided that you do not advertise this Package
+as a product of your own.
+   
+6. The scripts and library files supplied as input to or produced as
+output from the programs of this Package do not automatically fall
+under the copyright of this Package, but belong to whomever generated
+them, and may be sold commercially, and may be aggregated with this
+Package.
+   
+7. Scripts, suites, or programs supplied by you that depend on or
+otherwise make use of this Package shall not be considered part of
+this Package.
+   
+8. The name of the Copyright Holder may not be used to endorse or
+promote products derived from this software without specific prior
+written permission.
+   
+9. THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
+WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+   
+                        The End
+
+
+http://www.spinwardstars.com/frontier/fal.html

src/portable_snprintf/Makefile

@@ -0,0 +1,54 @@
+# Make sure you include -DHAVE_SNPRINTF in CFLAGS if your system
+# does have snprintf!
+
+# If you need (long long int) support and you sprintf supports it,
+# define -DSNPRINTF_LONGLONG_SUPPORT
+vpath %.h ../../inc
+vpath %.a ../../lib
+
+CC      = gcc
+
+CFLAGS  = -DPREFER_PORTABLE_SNPRINTF -O3 \
+	  -Wall -Wpointer-arith -Wwrite-strings \
+	  -Wcast-qual -Wcast-align -Waggregate-return \
+	  -Wmissing-prototypes -Wmissing-declarations \
+	  -Wshadow -Wstrict-prototypes
+	  
+CFLAGS+=-DSNPRINTF_LONGLONG_SUPPORT -DHAVE_SNPRINTF
+CFLAGS+=-I../../inc/
+
+#	  -DNEED_ASPRINTF -DNEED_ASNPRINTF -DNEED_VASPRINTF -DNEED_VASNPRINTF
+#	  -DNEED_SNPRINTF_ONLY
+
+# Digital Unix: native compiler usually produces better code than gcc
+#CC     = cc
+#CFLAGS = -DPREFER_PORTABLE_SNPRINTF -O4 -std1 -arch host
+
+# Recommend to leave COMPATIBILITY empty for normal use.
+# Should be set for bug compatibility when running tests
+# too keep them less chatty.
+COMPATIBILITY =
+
+#COMPATIBILITY = -DSOLARIS_BUG_COMPATIBLE
+#COMPATIBILITY = -DHPUX_BUG_COMPATIBLE
+#COMPATIBILITY = -DDIGITAL_UNIX_BUG_COMPATIBLE
+#COMPATIBILITY = -DPERL_BUG_COMPATIBLE
+#COMPATIBILITY = -DLINUX_COMPATIBLE
+
+SRC=snprintf.c
+OBJS=$(SRC:.c=.o)
+
+TARGET=libMESA_snprintf.a libMESA_snprintf.so
+
+all:$(TARGET)
+	cp -f $(TARGET) ../../lib
+
+libMESA_snprintf.a:$(OBJS)
+	ar cqs $@ $<
+
+libMESA_snprintf.so:$(OBJS)
+	$(CC) $(CFLAGS) $(LIB) -shared $< -o $@
+.c.o:
+
+clean :
+	rm -f $(OBJS) $(TARGET)

src/portable_snprintf/README

@@ -0,0 +1,283 @@
+
+                                  snprintf.c
+                   - a portable implementation of snprintf,
+       including vsnprintf.c, asnprintf, vasnprintf, asprintf, vasprintf
+                                       
+   snprintf is a routine to convert numeric and string arguments to
+   formatted strings. It is similar to sprintf(3) provided in a system's
+   C library, yet it requires an additional argument - the buffer size -
+   and it guarantees never to store anything beyond the given buffer,
+   regardless of the format or arguments to be formatted. Some newer
+   operating systems do provide snprintf in their C library, but many do
+   not or do provide an inadequate (slow or idiosyncratic) version, which
+   calls for a portable implementation of this routine.
+   
+Author
+
+   Mark Martinec <mark.martinec@ijs.si>, April 1999, June 2000
+   Copyright <20> 1999, Mark Martinec
+   
+Terms and conditions ...
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the Frontier Artistic License which comes with
+   this Kit.
+   
+Features
+
+     * careful adherence to specs regarding flags, field width and
+       precision;
+     * good performance for large string handling (large format, large
+       argument or large paddings). Performance is similar to system's
+       sprintf and in several cases significantly better (make sure you
+       compile with optimizations turned on, tell the compiler the code
+       is strict ANSI if necessary to give it more freedom for
+       optimizations);
+     * return value semantics per ISO/IEC 9899:1999 ("ISO C99");
+     * written in standard ISO/ANSI C - requires an ANSI C compiler.
+       
+Supported conversion specifiers and data types
+
+   This snprintf only supports the following conversion specifiers: s, c,
+   d, o, u, x, X, p (and synonyms: i, D, U, O - see below) with flags:
+   '-', '+', ' ', '0' and '#'. An asterisk is supported for field width
+   as well as precision.
+   
+   Length modifiers 'h' (short int), 'l' (long int), and 'll' (long long
+   int) are supported.
+   
+   NOTE:
+   
+     If macro SNPRINTF_LONGLONG_SUPPORT is not defined (default) the
+     length modifier 'll' is recognized but treated the same as 'l',
+     which may cause argument value truncation! Defining
+     SNPRINTF_LONGLONG_SUPPORT requires that your system's sprintf also
+     handles length modifier 'll'. long long int is a language extension
+     which may not be portable.
+     
+   Conversion of numeric data (conversion specifiers d, o, u, x, X, p)
+   with length modifiers (none or h, l, ll) is left to the system routine
+   sprintf, but all handling of flags, field width and precision as well
+   as c and s conversions is done very carefully by this portable
+   routine. If a string precision (truncation) is specified (e.g. %.8s)
+   it is guaranteed the string beyond the specified precision will not be
+   referenced.
+   
+   Length modifiers h, l and ll are ignored for c and s conversions (data
+   types wint_t and wchar_t are not supported).
+   
+   The following common synonyms for conversion characters are supported:
+     * i is a synonym for d
+     * D is a synonym for ld, explicit length modifiers are ignored
+     * U is a synonym for lu, explicit length modifiers are ignored
+     * O is a synonym for lo, explicit length modifiers are ignored
+       
+   The D, O and U conversion characters are nonstandard, they are
+   supported for backward compatibility only, and should not be used for
+   new code.
+   
+   The following is specifically not supported:
+     * flag ' (thousands' grouping character) is recognized but ignored
+     * numeric conversion specifiers: f, e, E, g, G and synonym F, as
+       well as the new a and A conversion specifiers
+     * length modifier 'L' (long double) and 'q' (quad - use 'll'
+       instead)
+     * wide character/string conversions: lc, ls, and nonstandard
+       synonyms C and S
+     * writeback of converted string length: conversion character n
+     * the n$ specification for direct reference to n-th argument
+     * locales
+       
+   It is permitted for str_m to be zero, and it is permitted to specify
+   NULL pointer for resulting string argument if str_m is zero (as per
+   ISO C99).
+   
+   The return value is the number of characters which would be generated
+   for the given input, excluding the trailing null. If this value is
+   greater or equal to str_m, not all characters from the result have
+   been stored in str, output bytes beyond the (str_m-1) -th character
+   are discarded. If str_m is greater than zero it is guaranteed the
+   resulting string will be null-terminated.
+   
+   NOTE that this matches the ISO C99, OpenBSD, and GNU C library 2.1,
+   but is different from some older and vendor implementations, and is
+   also different from XPG, XSH5, SUSv2 specifications. For historical
+   discussion on changes in the semantics and standards of snprintf see
+   printf(3) man page in the Linux programmers manual.
+   
+   Routines asprintf and vasprintf return a pointer (in the ptr argument)
+   to a buffer sufficiently large to hold the resulting string. This
+   pointer should be passed to free(3) to release the allocated storage
+   when it is no longer needed. If sufficient space cannot be allocated,
+   these functions will return -1 and set ptr to be a NULL pointer. These
+   two routines are a GNU C library extensions (glibc).
+   
+   Routines asnprintf and vasnprintf are similar to asprintf and
+   vasprintf, yet, like snprintf and vsnprintf counterparts, will write
+   at most str_m-1 characters into the allocated output string, the last
+   character in the allocated buffer then gets the terminating null. If
+   the formatted string length (the return value) is greater than or
+   equal to the str_m argument, the resulting string was truncated and
+   some of the formatted characters were discarded. These routines
+   present a handy way to limit the amount of allocated memory to some
+   sane value.
+   
+Availability
+
+   http://www.ijs.si/software/snprintf/
+     * snprintf_1.3.tar.gz (1999-06-30), md5 sum: snprintf_1.3.tar.gz.md5
+     * snprintf_2.1.tar.gz (2000-07-14), md5 sum: snprintf_2.1.tar.gz.md5
+     * snprintf_2.2.tar.gz (2000-10-18), md5 sum: snprintf_2.2.tar.gz.md5
+       
+Mailing list
+
+   There is a very low-traffic mailing list snprintf-announce@ijs.si
+   where announcements about new versions will be posted as well as
+   warnings about threatening bugs if discovered. The posting is
+   restricted to snprintf developer(s).
+   
+   To subscribe to (or unsubscribe from) the mailing list please visit
+   the list server's web page
+   http://mailman.ijs.si/listinfo/snprintf-announce
+   
+   You can also subscribe to the list by mailing the command SUBSCRIBE
+   either in the subject or in the message body to the address
+   snprintf-announce-request@ijs.si . You will be asked for confirmation
+   before subscription will be effective.
+   
+   The list of members is only accessible to the list administrator, so
+   there is no need for concern about automatic e-mail address gatherers.
+   
+   Questions about the mailing list and concerns for the attention of a
+   person should be sent to snprintf-announce-admin@ijs.si
+   
+   There is no general discussion list about portable snprintf at the
+   moment. Please send comments and suggestion to the author.
+   
+Revision history
+
+   Version 1.3 fixes a runaway loop problem from 1.2. Please upgrade.
+   
+   1999-06-30 V1.3 Mark Martinec <mark.martinec@ijs.si>
+          
+          + fixed runaway loop (eventually crashing when str_l wraps
+            beyond 2^31) while copying format string without conversion
+            specifiers to a buffer that is too short (thanks to Edwin
+            Young <edwiny@autonomy.com> for spotting the problem);
+          + added macros PORTABLE_SNPRINTF_VERSION_(MAJOR|MINOR) to
+            snprintf.h
+            
+   2000-02-14 V2.0 (never released) Mark Martinec <mark.martinec@ijs.si>
+          
+          + relaxed license terms: The Artistic License now applies. You
+            may still apply the GNU GENERAL PUBLIC LICENSE as was
+            distributed with previous versions, if you prefer;
+          + changed REVISION HISTORY dates to use ISO 8601 date format;
+          + added vsnprintf (patch also independently proposed by Caol<6F>n
+            McNamara 2000-05-04, and Keith M Willenson 2000-06-01)
+            
+   2000-06-27 V2.1 Mark Martinec <mark.martinec@ijs.si>
+          
+          + removed POSIX check for str_m < 1; value 0 for str_m is
+            allowed by ISO C99 (and GNU C library 2.1) (pointed out on
+            2000-05-04 by Caol<6F>n McNamara, caolan@ csn dot ul dot ie).
+            Besides relaxed license this change in standards adherence is
+            the main reason to bump up the major version number;
+          + added nonstandard routines asnprintf, vasnprintf, asprintf,
+            vasprintf that dynamically allocate storage for the resulting
+            string; these routines are not compiled by default, see
+            comments where NEED_V?ASN?PRINTF macros are defined;
+          + autoconf contributed by Caol<6F>n McNamara
+            
+   2000-10-06 V2.2 Mark Martinec <mark.martinec@ijs.si>
+          
+          + BUG FIX: the %c conversion used a temporary variable that was
+            no longer in scope when referenced, possibly causing
+            incorrect resulting character;
+          + BUG FIX: make precision and minimal field width unsigned to
+            handle huge values (2^31 <= n < 2^32) correctly; also be more
+            careful in the use of signed/unsigned/size_t internal
+            variables -- probably more careful than many vendor
+            implementations, but there may still be a case where huge
+            values of str_m, precision or minimal field could cause
+            incorrect behaviour;
+          + use separate variables for signed/unsigned arguments, and for
+            short/int, long, and long long argument lengths to avoid
+            possible incompatibilities on certain computer architectures.
+            Also use separate variable arg_sign to hold sign of a numeric
+            argument, to make code more transparent;
+          + some fiddling with zero padding and "0x" to make it Linux
+            compatible;
+          + systematically use macros fast_memcpy and fast_memset instead
+            of case-by-case hand optimization; determine some breakeven
+            string lengths for different architectures;
+          + terminology change: format -> conversion specifier, C9x ->
+            ISO/IEC 9899:1999 ("ISO C99"), alternative form -> alternate
+            form, data type modifier -> length modifier;
+          + several comments rephrased and new ones added;
+          + make compiler not complain about 'credits' defined but not
+            used;
+            
+Other implementations of snprintf
+
+   I am aware of some other (more or less) portable implementations of
+   snprintf. I do not claim they are free software - please refer to
+   their respective copyright and licensing terms. If you know of other
+   versions please let me know.
+     * a very thorough implementation (src/util_snprintf.c) by the Apache
+       Group distributed with the Apache web server -
+       http://www.apache.org/ . Does its own floating point conversions
+       using routines ecvt(3), fcvt(3) and gcvt(3) from the standard C
+       library or from the GNU libc.
+       This is from the code:
+       
+     This software [...] was originally based on public domain software
+     written at the National Center for Supercomputing Applications,
+     University of Illinois, Urbana-Champaign.
+     [...] This code is based on, and used with the permission of, the
+     SIO stdio-replacement strx_* functions by Panos Tsirigotis
+     <panos@alumni.cs.colorado.edu> for xinetd.
+     * QCI Utilities use a modified version of snprintf from the Apache
+       group.
+     * implementations as distributed with OpenBSD, FreeBSD, and NetBSD
+       are all wrappers to vfprintf.c, which is derived from software
+       contributed to Berkeley by Chris Torek.
+     * implementation from Prof. Patrick Powell <papowell@sdsu.edu>,
+       Dept. Electrical and Computer Engineering, San Diego State
+       University, San Diego, CA 92182-1309, published in Bugtraq
+       archives for 3rd quarter (Jul-Aug) 1995. No floating point
+       conversions.
+     * Brandon Long's <blong@fiction.net> modified version of Prof.
+       Patrick Powell's snprintf with contributions from others. With
+       minimal floating point support.
+     * implementation (src/snprintf.c) as distributed with sendmail -
+       http://www.sendmail.org/ is a cleaned up Prof. Patrick Powell's
+       version to compile properly and to support .precision and %lx.
+     * implementation from Caol<6F>n McNamara available at
+       http://www.csn.ul.ie/~caolan/publink/snprintf-1.1.tar.gz, handles
+       floating point.
+     * implementation used by newlog (a replacement for syslog(3)) made
+       available by the SOS Corporation. Enabling floating point support
+       is a compile-time option.
+     * implementation by Michael Richardson <mcr@metis.milkyway.com> is
+       available at http://sandelman.ottawa.on.ca/SSW/snp/snp.html. It is
+       based on BSD44-lite's vfprintf() call, modified to function on
+       SunOS. Needs internal routines from the 4.4 strtod (included),
+       requires GCC to compile the long long (aka quad_t) portions.
+     * implementation from Tomi Salo <ttsalo@ssh.fi> distributed with SSH
+       2.0 Unix Server. Not in public domain. Floating point conversions
+       done by system's sprintf.
+     * and for completeness: my portable version described in this very
+       document available at http://www.ijs.si/software/snprintf/ .
+       
+   In retrospect, it appears that a lot of effort was wasted by many
+   people for not being aware of what others are doing. Sigh.
+   
+   Also of interest: The Approved Base Working Group Resolution for XSH5,
+   Ref: bwg98-006, Topic: snprintf.
+     _________________________________________________________________
+   
+   mm
+   Last updated: 2000-10-18
+   
+   Valid HTML 4.0! 

src/portable_snprintf/README.html

@@ -0,0 +1,382 @@
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
+<html>
+<head>
+<link rev="made" href="mailto:mark.martinec@ijs.si">
+<title>
+snprintf.c - a portable implementation of snprintf
+(including vsnprintf.c, asnprintf, vasnprintf, asprintf, vasprintf)
+</title>
+<meta http-equiv="Content-Language" content="en">
+<meta name="author"    content="Mark Martinec">
+<meta name="copyright" content="Copyright 2000 Mark Martinec, All Rights Reserved">
+<meta name="date"      content="2000-10-18">
+<meta name="keywords" lang="en"
+ content="snprintf,portable,vsnprintf,asnprintf,vasnprintf,asprintf,vasprintf
+          ISO/IEC 9899:1999,ISO C99,ISO C9x,POSIX">
+<style type="text/css">
+<!--
+  body { background: white; color: black }
+ -->
+</style>
+</head>
+<body>
+<h1><b>snprintf.c</b>
+<br> - a portable implementation of snprintf,
+<br><font size="+1">including
+vsnprintf.c, asnprintf, vasnprintf, asprintf, vasprintf</font>
+</h1>
+
+<p><b>snprintf</b> is a routine to convert numeric and string arguments
+to formatted strings. It is similar to sprintf(3) provided in a
+system's C library, yet it requires an additional argument - the buffer
+size - and it guarantees never to store anything beyond the given buffer,
+regardless of the format or arguments to be formatted. Some newer
+operating systems do provide <b>snprintf</b> in their C library,
+but many do not or do provide an inadequate (slow or idiosyncratic)
+version, which calls for a portable implementation of this routine.
+
+<h2>Author</h2>
+
+<p><a href="http://www.ijs.si/people/mark/">Mark Martinec</a>
+&lt;<a href="mailto:mark.martinec@ijs.si">mark.martinec@ijs.si</a>&gt;,
+April 1999, June 2000
+<br>Copyright &copy; 1999, Mark Martinec
+
+<h2>Terms and conditions ...</h2>
+
+<p>This program is free software; you can redistribute it
+and/or modify it under the terms of the
+<i><a href="./LICENSE.txt">Frontier Artistic License</a></i>
+which comes with this Kit.
+
+<h2>Features</h2>
+
+<ul>
+<li>careful adherence to specs regarding flags, field width and precision;
+<li>good performance for large string handling (large format, large argument
+or large paddings). Performance is similar to system's <b>sprintf</b>
+and in several cases significantly better (make sure you compile with
+optimizations turned on, tell the compiler the code is strict ANSI
+if necessary to give it more freedom for optimizations);
+<li>return value semantics per ISO/IEC 9899:1999 ("ISO C99");
+<li>written in standard ISO/ANSI C - requires an ANSI C compiler.
+</ul>
+
+<h2>Supported conversion specifiers and data types</h2>
+
+<p>This <b>snprintf</b> only supports the following conversion specifiers:
+s, c, d, o, u, x, X, p  (and synonyms: i, D, U, O - see below)
+with flags: '-', '+', '&nbsp;', '0' and '#'.
+An asterisk is supported for field width as well as precision.
+
+<p>Length modifiers 'h' (<i>short int</i>), 'l' (<i>long int</i>),
+and 'll' (<i>long long int</i>) are supported.
+
+<p>NOTE:
+<blockquote>
+If macro SNPRINTF_LONGLONG_SUPPORT is not defined (default)
+the length modifier 'll' is recognized but treated the same as 'l',
+which may cause argument value truncation!
+Defining SNPRINTF_LONGLONG_SUPPORT requires that your system's
+<b>sprintf</b> also handles length modifier 'll'.
+<i>long long int</i> is a language extension which may not be portable.
+</blockquote>
+
+<p>Conversion of numeric data (conversion specifiers d, o, u, x, X, p)
+with length modifiers (none or h, l, ll) is left to the system
+routine <b>sprintf</b>, but all handling of flags, field width and precision
+as well as c and s conversions is done very carefully by this portable routine.
+If a string precision (truncation) is specified (e.g. %.8s) it is
+guaranteed the string beyond the specified precision will not be referenced.
+
+<p>Length modifiers h, l and ll are ignored for c and s conversions
+(data types <i>wint_t</i> and <i>wchar_t</i> are not supported).
+
+<p>The following common synonyms for conversion characters are supported:
+<ul>
+<li>i is a synonym for d
+<li>D is a synonym for ld, explicit length modifiers are ignored
+<li>U is a synonym for lu, explicit length modifiers are ignored
+<li>O is a synonym for lo, explicit length modifiers are ignored
+</ul>
+The D, O and U conversion characters are nonstandard, they are supported
+for backward compatibility only, and should not be used for new code.
+
+<p>The following is specifically <b>not</b> supported:
+<ul>
+<li>flag ' (thousands' grouping character) is recognized but ignored
+<li>numeric conversion specifiers: f, e, E, g, G and synonym F,
+as well as the new a and A conversion specifiers
+<li>length modifier 'L' (<i>long double</i>)
+and 'q' (<i>quad</i> - use 'll' instead)
+<li>wide character/string conversions: lc, ls, and nonstandard
+synonyms C and S
+<li>writeback of converted string length: conversion character n
+<li>the n$ specification for direct reference to n-th argument
+<li>locales
+</ul>
+
+<p>It is permitted for str_m to be zero, and it is permitted to specify NULL
+pointer for resulting string argument if str_m is zero (as per ISO C99).
+
+<p>The return value is the number of characters which would be generated
+for the given input, <i>excluding</i> the trailing null. If this value
+is greater or equal to str_m, not all characters from the result
+have been stored in str, output bytes beyond the (str_m-1) -th character
+are discarded. If str_m is greater than zero it is guaranteed
+the resulting string will be null-terminated.
+
+<p>NOTE that this matches the ISO C99, OpenBSD, and GNU C library 2.1,
+but is different from some older and vendor implementations,
+and is also different from XPG, XSH5, SUSv2 specifications.
+For historical discussion on changes in the semantics and standards
+of snprintf see printf(3) man page in the Linux programmers manual.
+
+<p>Routines asprintf and vasprintf return a pointer (in the ptr argument)
+to a buffer sufficiently large to hold the resulting string. This pointer
+should be passed to free(3) to release the allocated storage when it is
+no longer needed. If sufficient space cannot be allocated, these functions
+will return -1 and set ptr to be a NULL pointer. These two routines are a
+GNU C library extensions (glibc).
+
+<p>Routines asnprintf and vasnprintf are similar to asprintf and vasprintf,
+yet, like snprintf and vsnprintf counterparts, will write at most str_m-1
+characters into the allocated output string, the last character in the
+allocated buffer then gets the terminating null. If the formatted string
+length (the return value) is greater than or equal to the str_m argument,
+the resulting string was truncated and some of the formatted characters
+were discarded. These routines present a handy way to limit the amount
+of allocated memory to some sane value.
+
+<h2>Availability</h2>
+
+<p><a href="http://www.ijs.si/software/snprintf/"
+>http://www.ijs.si/software/snprintf/</a>
+
+<ul>
+<li>
+<a href="./snprintf_1.3.tar.gz">snprintf_1.3.tar.gz</a> (1999-06-30),
+md5 sum: <a href="./snprintf_1.3.tar.gz.md5">snprintf_1.3.tar.gz.md5</a>
+
+<li>
+<a href="./snprintf_2.1.tar.gz">snprintf_2.1.tar.gz</a> (2000-07-14),
+md5 sum: <a href="./snprintf_2.1.tar.gz.md5">snprintf_2.1.tar.gz.md5</a>
+
+<li>
+<a href="./snprintf_2.2.tar.gz">snprintf_2.2.tar.gz</a> (2000-10-18),
+md5 sum: <a href="./snprintf_2.2.tar.gz.md5">snprintf_2.2.tar.gz.md5</a>
+</ul>
+
+
+<h2>Mailing list</h2>
+
+<p>There is a very low-traffic mailing list <i>snprintf-announce@ijs.si</i>
+where announcements about new versions will be posted
+as well as warnings about threatening bugs if discovered.
+The posting is restricted to snprintf developer(s).
+
+<p>To subscribe to (or unsubscribe from) the mailing list
+please visit the list server's web page
+<a href="http://mailman.ijs.si/listinfo/snprintf-announce"
+>http://mailman.ijs.si/listinfo/snprintf-announce</a>
+
+<p>You can also subscribe to the list by mailing
+the command SUBSCRIBE either in the subject or in the message body
+to the address <a href="mailto:snprintf-announce-request@ijs.si"
+>snprintf-announce-request@ijs.si</a> . You will be asked for
+confirmation before subscription will be effective.
+
+<p>The list of members is only accessible to the list administrator,
+so there is no need for concern about automatic e-mail address gatherers.
+
+<p>Questions about the mailing list and concerns for the attention
+of a person should be sent to <a href="mailto:snprintf-announce-admin@ijs.si"
+>snprintf-announce-admin@ijs.si</a>
+
+<p>There is no <i>general</i> discussion list about portable snprintf
+at the moment. Please send comments and suggestion to the author.
+
+
+<h2>Revision history</h2>
+
+<p><b>Version 1.3 fixes a runaway loop problem from 1.2. Please upgrade.</b>
+
+<dl>
+<dt>1999-06-30	V1.3  Mark Martinec &lt;mark.martinec@ijs.si&gt;
+<dd><ul>
+<li>fixed runaway loop (eventually crashing when str_l wraps
+  beyond 2^31) while copying format string without
+  conversion specifiers to a buffer that is too short
+  (thanks to Edwin Young &lt;edwiny@autonomy.com&gt; for spotting the problem);
+<li>added macros PORTABLE_SNPRINTF_VERSION_(MAJOR|MINOR) to snprintf.h
+</ul>
+
+<dt>2000-02-14	V2.0 (never released) Mark Martinec &lt;mark.martinec@ijs.si&gt;
+<dd><ul>
+<li>relaxed license terms:
+  <a href="./LICENSE.txt">The Artistic License</a> now applies.
+  You may still apply the GNU GENERAL PUBLIC LICENSE
+  as was distributed with previous versions, if you prefer;
+<li>changed REVISION HISTORY dates to use
+  <a href="http://www.cl.cam.ac.uk/~mgk25/iso-time.html">ISO 8601
+  date format</a>;
+<li>added vsnprintf (patch also independently proposed by
+  Caol&aacute;n McNamara 2000-05-04, and Keith M Willenson 2000-06-01)
+</ul>
+
+<dt>2000-06-27	V2.1  Mark Martinec &lt;mark.martinec@ijs.si&gt;
+<dd><ul>
+<li>removed POSIX check for str_m &lt; 1; value 0 for str_m is
+  allowed by ISO C99 (and GNU C library 2.1) (pointed out
+  on 2000-05-04 by Caol&aacute;n McNamara, caolan@ csn dot ul dot ie).
+  Besides relaxed license this change in standards adherence
+  is the main reason to bump up the major version number;
+<li>added nonstandard routines asnprintf, vasnprintf, asprintf,
+  vasprintf that dynamically allocate storage for the
+  resulting string; these routines are not compiled by default,
+  see comments where NEED_V?ASN?PRINTF macros are defined;
+<li>autoconf contributed by Caol&aacute;n McNamara
+</ul>
+
+<dt>2000-10-06	V2.2  Mark Martinec &lt;mark.martinec@ijs.si&gt;
+<dd><ul>
+<li><b>BUG FIX</b>: the %c conversion used a temporary variable
+  that was no longer in scope when referenced,
+  possibly causing incorrect resulting character;
+<li>BUG FIX: make precision and minimal field width unsigned
+  to handle huge values (2^31 &lt;= n &lt; 2^32) correctly;
+  also be more careful in the use of signed/unsigned/size_t
+  internal variables -- probably more careful than many
+  vendor implementations, but there may still be a case
+  where huge values of str_m, precision or minimal field
+  could cause incorrect behaviour;
+<li>use separate variables for signed/unsigned arguments,
+  and for short/int, long, and long long argument lengths
+  to avoid possible incompatibilities on certain
+  computer architectures. Also use separate variable
+  arg_sign to hold sign of a numeric argument,
+  to make code more transparent;
+<li>some fiddling with zero padding and "0x" to make it
+  Linux compatible;
+<li>systematically use macros fast_memcpy and fast_memset
+  instead of case-by-case hand optimization; determine some
+  breakeven string lengths for different architectures;
+<li>terminology change: <i>format</i> -&gt; <i>conversion specifier</i>,
+  <i>C9x</i> -&gt; <i>ISO/IEC 9899:1999 ("ISO C99")</i>,
+  <i>alternative form</i> -&gt; <i>alternate form</i>,
+  <i>data type modifier</i> -&gt; <i>length modifier</i>;
+<li>several comments rephrased and new ones added;
+<li>make compiler not complain about 'credits' defined but
+  not used;
+</ul>
+</dl>
+
+<h2>Other implementations of snprintf</h2>
+
+<p>I am aware of some other (more or less) portable implementations
+of <b>snprintf</b>. I do not claim they are free software - please refer
+to their respective copyright and licensing terms.
+If you know of other versions please let
+<a href="http://www.ijs.si/people/mark/">me</a> know.
+
+<ul>
+<li>a very thorough implementation (src/util_snprintf.c)
+by the Apache Group distributed with the
+<a href="http://www.apache.org/">Apache web server
+- http://www.apache.org/</a> .
+Does its own floating point conversions using routines
+ecvt(3), fcvt(3) and gcvt(3) from the standard C library
+or from the GNU libc.
+
+<br>This is from the code:
+<blockquote>
+This software [...] was originally based
+on public domain software written at the
+<a href="http://www.ncsa.uiuc.edu/ncsa.html">National Center
+for Supercomputing Applications</a>, University of Illinois,
+Urbana-Champaign.<br>
+[...] This code is based on, and used with the permission of,
+the SIO stdio-replacement strx_* functions by Panos Tsirigotis
+&lt;<a href="mailto:panos@alumni.cs.colorado.edu">panos@alumni.cs.colorado.edu</a>&gt; for xinetd.
+</blockquote>
+
+<li><a href="http://www.qlue.com/downloads/c_utils_README.html">QCI
+Utilities</a> use a modified version of snprintf from the Apache group.
+
+<li>implementations as distributed with
+<a href="http://www.openbsd.org/cgi-bin/cvsweb/src/lib/libc/stdio/">OpenBSD</a>,
+<a href="http://www.freebsd.org/cgi/cvsweb.cgi/src/lib/libc/stdio/">FreeBSD</a>, and
+<a href="http://cvsweb.netbsd.org/cgi-bin/cvsweb.cgi/basesrc/lib/libc/stdio/">NetBSD</a>
+are all wrappers to vfprintf.c, which is derived from software
+contributed to Berkeley by Chris Torek.
+
+<li>implementation from Prof. Patrick Powell
+&lt;<a href="mailto:papowell@sdsu.edu">papowell@sdsu.edu</a>&gt;,
+Dept. Electrical and Computer Engineering, San Diego State University,
+San Diego, CA 92182-1309, published in
+<a href="http://www.geek-girl.com/bugtraq/1995_3/0217.html">Bugtraq
+archives for 3rd quarter (Jul-Aug) 1995</a>.
+No floating point conversions.
+
+<li>Brandon Long's
+&lt;<a href="mailto:blong@fiction.net">blong@fiction.net</a>&gt;
+<a href="http://www.fiction.net/~blong/programs/">modified version</a>
+of Prof. Patrick Powell's snprintf with contributions from others.
+With minimal floating point support.
+
+<li>implementation (src/snprintf.c) as distributed with
+<a href="http://www.sendmail.org/">sendmail - http://www.sendmail.org/</a>
+is a cleaned up Prof. Patrick Powell's version
+to compile properly and to support .precision and %lx.
+
+<li>implementation from <a href="http://www.csn.ul.ie/~caolan/"
+>Caol&aacute;n McNamara</a> available at
+<a href="http://www.csn.ul.ie/~caolan/publink/snprintf-1.1.tar.gz"
+>http://www.csn.ul.ie/~caolan/publink/snprintf-1.1.tar.gz</a>,
+handles floating point.
+
+<li>implementation used by
+<a href="ftp://ftp.soscorp.com/pub/sos/lib">newlog</a>
+(a replacement for syslog(3)) made available by
+the <a href="http://www.soscorp.com">SOS Corporation</a>.
+Enabling floating point support is a compile-time option.
+
+<li>implementation by Michael Richardson
+&lt;<a href="mailto:mcr@metis.milkyway.com">mcr@metis.milkyway.com</a>&gt;
+is available at
+<a href="http://sandelman.ottawa.on.ca/SSW/snp/snp.html"
+>http://sandelman.ottawa.on.ca/SSW/snp/snp.html</a>.
+It is based on BSD44-lite's vfprintf() call, modified to function
+on SunOS. Needs internal routines from the 4.4 strtod (included),
+requires GCC to compile the long long (aka quad_t) portions. 
+
+<li>implementation from Tomi Salo
+&lt;<a href="mailto:ttsalo@ssh.fi">ttsalo@ssh.fi</a>&gt;
+distributed with
+<a href="http://www.Europe.DataFellows.com/f-secure/ssh/">SSH 2.0
+Unix Server</a>. Not in public domain.
+Floating point conversions done by system's sprintf.
+
+<li>and for completeness: <a href="http://www.ijs.si/people/mark/">my</a>
+portable version described in this very document available at
+<a href="http://www.ijs.si/software/snprintf/"
+>http://www.ijs.si/software/snprintf/</a> .
+</ul>
+
+In retrospect, it appears that a lot of effort was wasted by many
+people for not being aware of what others are doing. Sigh.
+
+<p>Also of interest:
+<a href="http://www.opengroup.org/platform/resolutions/bwg98-006.html"
+>The Approved Base Working Group Resolution for XSH5,
+Ref: bwg98-006, Topic: snprintf</a>.
+
+<p><hr> 
+<i><a href="http://www.ijs.si/people/mark/">mm</a></i>
+<br>Last updated: 2000-10-18
+
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