qlibs:(logmsg)

📦 version 31, in alpine 3.24

🦋 qlibs manual: logmsg 🦋

✨ NAME ✨

logmsg — handle system errors and application log messages 💅

🌸 SYNTAX 🌸

#include "logmsg.h"

int logmsg(const char *who, int ecode, unsigned int classs, char *msg)

err_sys(w,e) logmsg(w,e,FATAL,"")
err_sys_plus(w,e,m) logmsg(w,e,FATAL,m)
err_tmp(w,e) logmsg(w,e,WARN,"")
err_tmp_plus(w,e,m) logmsg(w,e,WARN,m)
err_int(w,e,c) logmsg(w,e,c,"")
err_int_plus(w,e,c,m) logmsg(w,e,c,m)
log_who(w,m) logmsg(w,0,LOG,m)
log_anon(m) logmsg("",0,LOG,m)

💖 DESCRIPTION 💖

Okay so bestie, logmsg prints error, warning, or info/logging messages to stderr, and it may literally terminate the calling program depending on the class you give it 😭

  • who is the name of the program
  • ecode is an error code
  • class determines the behavior upon call
  • msg is the logging message

Read "error.h" to learn more about related constants 👑✨

🎀 ECODE 🎀

ecode is the error code, and it’s subject to be displayed in the log file and potentially used upon exit if the class equals ERROR, FATAL, or DROP 💀

To avoid conflicts with syscall error codes, application-defined error codes should be negative. The values -15, -100 and -111 are reserved for backward compatibility 🫶

🌈 CLASS 🌈

The class parameter indicates how the application handles exceptions and displays the log message. Vibe check:

  • LOG, INFO, ALERT, WARN — display message and continue operation ✨
  • DROP — display warning message and continue while returning to the calling program 🌀
  • USAGE, SYNTAX, FATAL, ERROR — display error message and exit application with error code 💥

INFO, ALERT, WARN, DROP, USAGE, and FATAL as well as ERROR display the respective class string like warning: in the log message, while LOG shows the log message only 👀

The class FATAL should be used for system error codes only, rather ERROR and WARN shall be set in conjunction with an application error/warning. Periodt 💅

🍓 MESSAGE 🍓

If the custom message msg is given, it will be printed additionally 💬

🧚 FORMAT 🧚

The log message format consists of the tokens who: (ecode) msg : msg 🪄

ecode is displayed only for classes FATAL, ERROR, or DROP. msg is the system’s explanation according to the variable errno if provided 🌸

💜 NOTES 💜

logmsg.c uses errstr.c routines. Error codes and classes are defined in error.h and included by logmsg.h 📚✨

🔥 EXIT CODE 🔥

logmsg exits ecode for classes ERROR, FATAL, SYNTAX, and USAGE, terminating the application 😵‍💫

🦋 HISTORY 🦋

Dan Bernstein used sets of strerr_dieY*() and strerr_warnY() messages which explicitely determine the message and behavior class. Other classes were occasionally defined on demand, such als usage() 👑

Kai Peter introduced the errmsg facility in his qlibs including a syslog compliant severity as second parameter 🌟

🎀 EXAMPLES 🎀

The macro definitions uses w for the calling program, e for error code, c for class, and m for message.

#include "logmsg.h"
#define WHO "my_prog"

err_sys(WHO,errno);
err_sys_plus(WHO,-111,"additional message");

err_tmp("",-100);
err_tmp_plus("",errno,"additional message");

log_who(WHO,"message");

log_anon() is like log_who() but doesn’t print the caller name 🙈

A user-defined message s can be build from multiple arguments by using the B (build) macro:

err_sys_plus((errno),B("unable to run: ",*argv));

🌟 SEE ALSO 🌟

syslog(3)

okay bye bestie 💖 this is section 3 of the qlibs manual, the (logmsg) page — mwah, slay, and happy logging ✨🎀

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