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我正在开发一个 C 程序，它使用 getopt 读取选项，然后遍历 argc 的其余部分以读取非可选参数。其中一些非可选参数是数字，其中一些是负数。常见问题，我知道，并且我理解修复只是在选项的结尾和非可选参数的开头之间放置一个“--”终止符。但是，这似乎不适用于我当前的设置。

这是读取可选和非可选参数的代码片段：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <math.h>

static const struct option longOpts[] = {
  {"inputconstheight", required_argument, 0, 'c'},
  {"inputheightfile", required_argument, 0, 'f'},
  {"alongtrackfile", required_argument, 0, 'g'},
  {"crosstrackfile", required_argument, 0, 'h'},
  {"lensconstant", required_argument, 0, 'm'},
  {"nonlinearoptics", required_argument, 0, 'n'},
  {"verbose", required_argument, 0, 'v'},
  {"rolloffset", required_argument, 0, 'x'},
  {"pitchoffset", required_argument, 0, 'y'},
  {"yawoffset", required_argument, 0, 'z'},
  {0, 0, 0, 0}
};

    int main(int argv, char **argc)
    {
    //skipping variable declaration for brevity
      while((opt = getopt_long(argv, argc, "cef:", longOpts, &longIndex))!=-1)
        {
          switch(opt)
        {
        case 'c': //constheight
          constantheightflag=1;
          constantheight=atof(optarg);
          break;
        case 'f': //inputheightfile
          constantheightflag=0;
          inputheightfilename=optarg;
          break;
        case 'g': //alongtrackfile
          inputalongtrackanglefilename=optarg;
          break;
        case 'h': //crosstrackfile
          inputcrosstrackanglefilename=optarg;
          break;
        case 'm': //lensconstant
          lensconstantflag=1;
          lensconstant=atof(optarg);
          break;
        case 'n': //nonlinearopticsflag
          nonlinearoptics=atoi(optarg);
          break;
        case 'v': //verbose
          verboseflag=1;
          break;
        case 'x': //rolloffset
          rolloffset=atof(optarg);
          break;
        case 'y': //pitchoffset
          pitchoffset=atof(optarg);
          break;
        case 'z': //yawoffset
          yawoffset=atof(optarg);
          break;
        case '?': 
          opterror=1;
          break;
        }
        }

      /*get non-optional arguments*/
      if((opterror==1)||((argv-optind)!=14)) {
        printf("Usage: geolocateplane -[cfghmnvxyz] -- outputlatfile outputlonfile imagexsize imageysize detectorxsize detectorysize fov_x fov_y lat lon alt roll pitch yaw\n");
        return 1;}
      else {
        outputlatfilename=argc[optind+0];
        outputlonfilename=argc[optind+1];
        imagexsize=atoi(argc[optind+2]);
        imageysize=atoi(argc[optind+3]);
        detectorxsize=atof(argc[optind+4]);
        detectorysize=atof(argc[optind+5]);
        fov_x=atof(argc[optind+6]);
        fov_y=atof(argc[optind+7]);
        cameralat=atof(argc[optind+8]);
        cameralon=atof(argc[optind+9]);
        cameraalt=atof(argc[optind+10]);
        cameraroll=atof(argc[optind+11]);
        camerapitch=atof(argc[optind+12]);
        camerayaw=atof(argc[optind+13]);
      }

这是函数调用和输出：

XXXXXX:~/XXXX$ /XXX/geolocateplane --inputconstheight=0 --nonlinearoptics=0 --lensconstant=5.9982225412 --rolloffset=-1.0 --pitchoffset=-0.7 --yawoffset=0.0 --verbose -- /XXX/PACS.20130122.red.020756.lat.dat /XXX/PACS.20130122.red.020756.lon.dat 1024 1024 18.0 18.0 110 110 36.2927288472 -119.6177822504 19875.8 -0.3 0.7 -26.9
/XXX/geolocateplane: invalid option -- '1'
/XXX/geolocateplane: invalid option -- '1'
/XXX/geolocateplane: invalid option -- '9'
//etc...etc...

知道为什么会发生这种情况，或者解决方法是什么？

4

1 回答 1

3

尝试 1

GNU getopt() doesn't work in a POSIX-ly correct manner unless you tell it to by setting POSIXLY_CORRECT=1 (any value does) in the environment. Having said that, your example should be OK because of the -- unless the option preceding the -- is supposed to take an argument, in which case the -- will be treated as the argument (to --verbose).

You've not shown the long options data structure, sadly.

Attempt 2

After the update, the problem is self-evident: --verbose was requiring an argument, so it did indeed chew up the -- as its option argument, leaving the rest of the line open to misinterpretation.

To set POSIXLY_CORRECT or not to set it

I'm not keen on the POSIX-ly incorrect behaviour, but other people like it. It means you have to be careful to use -- when you want the following arguments to be treated as non-option arguments.

However, setting POSIXLY_CORRECT can confuse things too. I have systems where I do and others where I don't set it. Both work.

On average, you're probably better off not setting it.

于 2014-04-30T17:12:32.217 回答