man.postnix Miscellaneous man pages of Plan 9 related material

     ERROR(2)                                                 ERROR(2)

     NAME
          estrdup, emalloc, erealloc, errinit, noerror, error, warn,
          catcherror, dprint - local error handling utilities

     SYNOPSIS
          #include <u.h>
          #include <libc.h>
          #include <error.h>

          char*     estrdup(char*)
          void*     emalloc(int);
          void*     erealloc(void*,int)
          void dbgprint(char* fmt, ...)
          void errinit(Error* e)
          void noerror(void)
          void error(char* msg, ...)
          void warn(char* msg, ...)
          void catcherror(void)

     DESCRIPTION
          These routiles are tools for error handling.  The ones named
          like standard functions with the letter e prepended behave
          as expected. However, they check that the standard routine
          did its work and call sysfatal(2) otherwise.

          catcherror, noerror, error, and errinit provide exeption
          handling for C, in the same style of the similar routines
          used in the kernel. The only difference is that errinit
          should be called before using any other. They can be used
          both with and without the thread(2) library.

          Dprint is like fprint(2) but prints only if the global debug
          is true. Beware that it is a macro and has a conditional
          statement. Always suround it with braces when used within if
          statements.

     SOURCE
          /sys/src/liberror

     EXAMPLE
          Catch an error, and raise one.

          void f(void)
          {
               error("raise this!");
          }

          void
          main(int argc, char **argv)
          {

     Page 1                       Plan 9            (printed 10/29/25)

     ERROR(2)                                                 ERROR(2)

               Error     e;
               errinit(&e);
               if (catcherror()){
                    sysfatal("catched: %r");
               }
               f();
               noerror();
          }

     Page 2                       Plan 9            (printed 10/29/25)