PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult the corresponding Linux  manual  page  for  details  of
       Linux behavior), or the interface may not be implemented on Linux.

NAME

       psiginfo, psignal — write signal information to standard error

SYNOPSIS

       #include <signal.h>

       void psiginfo(const siginfo_t *pinfo, const char *message);
       void psignal(int signum, const char *message);

DESCRIPTION

       The psiginfo() and psignal() functions shall write a language-dependent message associated
       with a signal number to the standard error stream as follows:

        *  First, if message is not a null pointer and  is  not  the  empty  string,  the  string
           pointed  to  by  the  message  argument  shall be written, followed by a <colon> and a
           <space>.

        *  Then the signal description string associated with signum or with the signal indicated
           by pinfo shall be written, followed by a <newline>.

       For  psiginfo(),  the  application shall ensure that the argument pinfo references a valid
       siginfo_t structure. For psignal(), if signum is not a valid signal number,  the  behavior
       is implementation-defined.

       The  psiginfo()  and  psignal() functions shall not change the orientation of the standard
       error stream.

       The psiginfo() and psignal() functions shall mark for update the  last  data  modification
       and  last  file  status  change  timestamps of the file associated with the standard error
       stream at some time between their  successful  completion  and  exit(),  abort(),  or  the
       completion of fflush() or fclose() on stderr.

       The  psiginfo()  and  psignal()  functions  shall  not  change  the  setting  of  errno if
       successful.

       On error, the psiginfo() and psignal() functions shall set the  error  indicator  for  the
       stream to which stderr points, and shall set errno to indicate the error.

       Since  no  value  is returned, an application wishing to check for error situations should
       set errno to 0, then call psiginfo() or psignal(), then check errno.

RETURN VALUE

       These functions shall not return a value.

ERRORS

       Refer to fputc().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       As an alternative to setting errno to zero before the call and checking if it is  non-zero
       afterwards,  applications  can  use  ferror()  to  detect  whether psiginfo() or psignal()
       encountered an error.

       An application wishing to use this method  to  check  for  error  situations  should  call
       clearerr(stderr)  before  calling  psiginfo() or psignal(), then if ferror(stderr) returns
       non-zero, the value of errno indicates which error occurred.

RATIONALE

       System  V  historically  has  psignal()  and  psiginfo()  in  <siginfo.h>.   However,  the
       <siginfo.h>  header  is  not specified in the Base Definitions volume of POSIX.1‐2017, and
       the type siginfo_t is defined in <signal.h>.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fputc(), perror(), strsignal()

       The Base Definitions volume of POSIX.1‐2017, <signal.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  by
       the  Institute  of  Electrical  and Electronics Engineers, Inc and The Open Group.  In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .