fits_header_list.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
 
int main( int argc, char *argv[] )
{
  fitsfile *fptr;         /* FITS file pointer, defined in fitsio.h */
  char card[FLEN_CARD];   /* Standard string lengths defined in fitsio.h */
  int status = 0;   /* CFITSIO status value MUST be initialized to zero! */
  int single = 0, hdupos = 0, nkeys = 0, ii = 0;
 
  int printhelp = ( argc == 2 && ( strcmp( argv[1], "-h" ) == 0 || strcmp( argv[1], "--help" ) == 0 ) );
 
  if ( printhelp || argc != 2 ) {
    fprintf( stderr, "Usage:  %s filename[ext] \n", argv[0] );
    fprintf( stderr, "\n" );
    fprintf( stderr, "List the FITS header keywords in a single extension, or, if \n" );
    fprintf( stderr, "ext is not given, list the keywords in all the extensions. \n" );
    fprintf( stderr, "\n" );
    fprintf( stderr, "Examples: \n" );
    fprintf( stderr, "   %s file.fits      - list every header in the file \n", argv[0] );
    fprintf( stderr, "   %s file.fits[0]   - list primary array header \n", argv[0] );
    fprintf( stderr, "   %s file.fits[2]   - list header of 2nd extension \n", argv[0] );
    fprintf( stderr, "   %s file.fits+2    - same as above \n", argv[0] );
    fprintf( stderr, "   %s file.fits[GTI] - list header of GTI extension\n", argv[0] );
    fprintf( stderr, "\n" );
    fprintf( stderr, "Note that it may be necessary to enclose the input file\n" );
    fprintf( stderr, "name in single quote characters on the Unix command line.\n" );
    return ( 0 );
  }
 
#if defined(PAGER) && defined(HAVE_POPEN) && defined(HAVE_PCLOSE)
  FILE *fout = popen( PAGER, "w" );
  if ( fout == NULL ) {
    fprintf( stderr, "Could not execute '%s'\n", PAGER );
    return ( 1 );
  }
#else
  FILE *fout = stdout;
#endif
 
  if ( !fits_open_file( &fptr, argv[1], READONLY, &status ) ) {
    fits_get_hdu_num( fptr, &hdupos ); /* Get the current HDU position */
 
    /* List only a single header if a specific extension was given */
    if ( hdupos != 1 || strchr( argv[1], '[' ) ) {
      single = 1;
    }
 
    for ( ; !status; hdupos++ ) { /* Main loop through each extension */
      fits_get_hdrspace( fptr, &nkeys, NULL, &status ); /* get # of keywords */
 
      fprintf( fout, "Header listing for HDU #%d:\n", hdupos );
 
      for ( ii = 1; ii <= nkeys; ii++ ) { /* Read and print each keywords */
 
        if ( fits_read_record( fptr, ii, card, &status ) ) {
          break;
        }
        fprintf( fout, "%s\n", card );
      }
      fprintf( fout, "END\n\n" ); /* terminate listing with END */
 
      if ( single ) {
        break;  /* quit if only listing a single header */
      }
 
      fits_movrel_hdu( fptr, 1, NULL, &status ); /* try to move to next HDU */
    }
 
    if ( status == END_OF_FILE ) {
      status = 0;  /* Reset after normal error */
    }
 
    fits_close_file( fptr, &status );
  }
 
#if defined(PAGER) && defined(HAVE_POPEN) && defined(HAVE_PCLOSE)
  pclose( fout );
#endif
 
  if ( status ) {
    fits_report_error( stderr, status ); /* print any error message */
  }
  return ( status );
}