The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008, 2016 Edition
Copyright © 2001-2016 The IEEE and The Open Group

#### NAME

> psiginfo, psignal - write signal information to standard error

#### SYNOPSIS

> ``[CX] #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.1-2008, and the type siginfo_t is defined in <signal.h>.

#### FUTURE DIRECTIONS

> None.

#### SEE ALSO

> fputc, perror, strsignal

> XBD <signal.h>

#### CHANGE HISTORY

> First released in Issue 7.

> POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0447 [399,428], XSH/TC1-2008/0448 [399], and XSH/TC1-2008/0449 [399,401] are applied.

> POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0260 [629] is applied.

End of informative text.

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