Specifications

Comedi
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Description
When a Comedilib function fails, it usually returns -1 or NULL, depending on the return type. An internal library variable stores
an error number, which can be retrieved with comedi_errno(). This error number can be converted to a human-readable form
by the functions comedi_perror() or comedi_strerror().
These functions are intended to mimic the behavior of the standard C library functions perror(), strerror(), and errno.
In particular, Comedilib functions sometimes return an error that is generated inside the C library; the comedi error message in
this case is the same as the C library.
The function comedi_perror() prints an error message to the standard error output stream stderr. The error message
consists of the argument string s, a colon, a space, a description of the error condition, and a new line.
5.4.5.4 comedi_strerror
comedi_strerror — return string describing Comedilib error code
Synopsis
#include <comedilib.h>
const char * comedi_strerror(int errnum);
Description
When a Comedilib function fails, it usually returns -1 or NULL, depending on the return type. An internal library variable stores
an error number, which can be retrieved with comedi_errno(). This error number can be converted to a human-readable form
by the functions comedi_perror() or comedi_strerror().
These functions are intended to mimic the behavior of the standard C library functions perror(), strerror(), and errno.
In particular, Comedilib functions sometimes return an error that is generated inside the C library; the comedi error message in
this case is the same as the C library.
The function comedi_strerror() returns a pointer to a character string describing the Comedilib error errnum. The returned
string may be modified by a subsequent call to a strerr() or perror() function (either the libc or Comedilib versions). An
unrecognized error number will return a pointer to the string ‘undefined error’, or similar.
5.4.6 Extensions
5.4.6.1 comedi_arm
comedi_arm — arm a subdevice
Synopsis
#include <comedilib.h>
int comedi_arm(comedi_t * device, unsigned int subdevice, unsigned int source);
Status
alpha