fits_header_getval.c

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//
// From https://heasarc.gsfc.nasa.gov/docs/software/fitsio/cexamples.html:
//
// FITS Tools: Handy FITS Utilities that illustrate how to use CFITSIO
// -------------------------------------------------------------------
//
// These are working programs written in ANSI C that illustrate how one can
// easily read, write, and modify FITS files using the CFITSIO library. Most of
// these programs are very short, containing only a few 10s of lines of
// executable code or less, yet they perform quite useful operations on FITS
// files. Copy the programs to your local machine, then compile, and link them
// with the CFITSIO library. A short description of how to use each program can
// be displayed by executing the program without any command line arguments.
//
// You may freely modify, reuse, and redistribute these programs as you wish. It
// is often easier to use one of these programs as a template when writing a new
// program, rather than coding the new program completely from scratch.
//
 
/**
 * \file
 * \ingroup lalpulsar_bin_FITSTools
 */
 
#include "config.h"
 
#include <string.h>
#include <stdio.h>
 
#if defined(HAVE_LIBCFITSIO)
// disable -Wstrict-prototypes flag for this header file as this causes
// a build failure for cfitsio-3.440+
#pragma GCC diagnostic ignored "-Wstrict-prototypes"
#include <fitsio.h>
#pragma GCC diagnostic pop
#else
#error CFITSIO library is not available
#endif
 
#if defined(HAVE_LIBCFITSIO)
 
#include <fitsio.h>
 
// If fffree() is missing, use free() instead
#if !defined(HAVE_FFFREE)
#undef fits_free_memory
#define fits_free_memory(ptr, status) free(ptr)
 
// If ffree() is present but not declared, declare it
#elif defined(HAVE_DECL_FFFREE) && !HAVE_DECL_FFFREE
int fffree( void *, int * );
#undef fits_free_memory
#define fits_free_memory fffree
 
#endif // ffree()
 
#endif // defined(HAVE_LIBCFITSIO)
 
int main( int argc, char *argv[] )
{
  fitsfile *fptr = 0;         /* FITS file pointer, defined in fitsio.h */
  char card[FLEN_CARD];
  char value[FLEN_VALUE], comment[FLEN_COMMENT];
  char *longvalue = 0;
  int status = 0;   /*  CFITSIO status value MUST be initialized to zero!  */
 
  int printhelp = ( argc == 2 && ( strcmp( argv[1], "-h" ) == 0 || strcmp( argv[1], "--help" ) == 0 ) );
 
  if ( printhelp || argc != 3 ) {
    fprintf( stderr, "Usage:  %s filename[ext] keyword\n", argv[0] );
    fprintf( stderr, "\n" );
    fprintf( stderr, "Print the current value of a header keyword.\n" );
    fprintf( stderr, "\n" );
    fprintf( stderr, "Examples: \n" );
    fprintf( stderr, "  %s file.fits dec      - list the DEC keyword \n", argv[0] );
    return ( 0 );
  }
 
  if ( !fits_open_file( &fptr, argv[1], READONLY, &status ) ) {
    if ( fits_read_card( fptr, argv[2], card, &status ) ) {
      fprintf( stderr, "Keyword does not exist\n" );
      return ( 1 );
    }
 
    fits_parse_value( card, value, comment, &status );
    if ( value[0] != '\'' ) {
      printf( "%s\n", value );
    } else {
      fits_read_key_longstr( fptr, argv[2], &longvalue, comment, &status );
      if ( longvalue ) {
        printf( "%s\n", longvalue );
        fits_free_memory( longvalue, &status );
      }
    }
 
    fits_close_file( fptr, &status );
  }    /* open_file */
 
  /* if error occured, print out error message */
  if ( status ) {
    fits_report_error( stderr, status );
  }
  return ( status );
}