OK, I have searched and found the following two * topics that started me in the right direction:
好的,我搜索过并发现以下两个*主题让我朝着正确的方向前进:
Argument-parsing helpers for C/UNIX
C / UNIX的参数解析助手
Pass arguments into C program from command line
从命令行将参数传递给C程序
NOTE: ALL CODE IS PSEUDO-CODE. WILL POST COMPILABLE CODE WHEN IT WORKS.
注意:所有代码都是PSEUDO-CODE。将在其工作时发布可编译代码。
However, I'm still completely confused on how to use getopt_long() in C. The program I'm writing is defined as having the following possible tags (but can include as many as you absolutely need, filling the rest in with empty values):
但是,我仍然对如何在C中使用getopt_long()感到困惑。我正在编写的程序被定义为具有以下可能的标记(但可以包含您绝对需要的数量,其余用空值填充) ):
id3tagEd filename -title "title" -artist "artist" -year 1991 -comment "comment" -album "album" -track 1
Now, from what I read, I need to utilize a struct for the long options, correct? If so, I wrote something along the lines of this:
现在,根据我的阅读,我需要利用一个结构来获取长期选项,对吗?如果是这样,我写了一些类似的东西:
struct fields field =
{
char *[] title;
char *[] artist;
char *[] album;
int year;
char *[] comment;
int track;
}
static struct options long_options[] =
{
{"title", 0, &field.title, 't'},
{"artist", 0, &field.artist, 'a'},
{"album", 0, &field.album, 'b'},
{"year", 0, &field.year, 'y'},
{"comment", 0, &field.comment, 'c'},
{"track", 0, &field.track, 'u'},
{0, 0, 0, 0}
}
Now, from what I gathered, I would be calling it via this:
现在,根据我收集的内容,我将通过以下方式调用它:
int option_index = 0;
int values = getopt_long(argc, argv, "tabycu", long_options, &option_index);
From here, could I strictly use the field struct and do what I need to within my program? However, if this is the case, can someone explain the whole long_options struct? I read the man pages and such, and I'm just utterly confused. By rereading the man pages, I can see I can set variables to null, and should be setting all my option requirements to "required_argument"? And then setting the structs via a while() loop? However, I see optarg being used. Is this set by getopt_long()? Or is it missing from the example?
从这里开始,我可以严格使用字段结构并在程序中执行我需要的操作吗?但是,如果是这种情况,有人可以解释整个long_options结构吗?我阅读了这些手册页,我只是完全糊涂了。通过重读手册页,我可以看到我可以将变量设置为null,并且应该将所有选项要求设置为“required_argument”?然后通过while()循环设置结构?但是,我看到正在使用optarg。这是由getopt_long()设置的吗?或者是否从示例中遗漏了?
And one last issue, I will always have an unnamed required option: filename, would I just use argv[0] to gain access to that? (Since I can assume it'll be first).
最后一个问题,我将始终有一个未命名的必需选项:filename,我只是使用argv [0]来获取访问权限吗? (因为我可以假设它将是第一个)。
On a side note, this is related to a homework problem, but it has nothing to do with fixing it, its more of a fundamental, have to understand argument passing and parsing in C via command line first.
在旁注中,这与作业问题有关,但它与修复它无关,它更多的是基础,必须首先通过命令行理解参数传递和解析。
2 个解决方案
#1
23
First off, you probably don't want 0
for the has_arg
field - it must be one of no_argument
, required_arguemnt
, or optional_argument
. In your case, all of them are going to be required_argument
. Besides that, you're not using the flag
field correctly - it has to be an integer pointer. If the corresponding flag is set, getopt_long()
will fill it in with the integer you passed in via the val
field. I don't think you need this feature at all. Here's a better (shortened) example for your case:
首先,你可能不希望has_arg字段为0 - 它必须是no_argument,required_arguemnt或optional_argument之一。在您的情况下,所有这些都将是required_argument。除此之外,你没有正确使用标志字段 - 它必须是一个整数指针。如果设置了相应的标志,getopt_long()将使用通过val字段传入的整数填充它。我认为你根本不需要这个功能。这是一个更好(缩短)的例子:
static struct option long_options[] =
{
{"title", required_argument, NULL, 't'},
{"artist", required_argument, NULL, 'a'},
{NULL, 0, NULL, 0}
};
Then later, you can use it appropriately (straight from the manpage, I added some comments):
然后,您可以适当地使用它(直接从联机帮助页,我添加了一些注释):
// loop over all of the options
while ((ch = getopt_long(argc, argv, "t:a:", long_options, NULL)) != -1)
{
// check to see if a single character or long option came through
switch (ch)
{
// short option 't'
case 't':
field.title = optarg; // or copy it if you want to
break;
// short option 'a'
case 'a':
field.artist = optarg; // or copy it if you want to
break;
}
}
You can extend for your other fields as necessary (and add some error handling, please!). Note - if you want to use -title
and -artist
like you have in your example, you'll need to use getopt_long_only()
, which doesn't have short options.
您可以根据需要扩展其他字段(并添加一些错误处理,请!)。注意 - 如果你想在你的例子中使用-title和-artist,你需要使用getopt_long_only(),它没有短选项。
As to your filename
option, you'll get that out as a '?'
from the getopt_long()
call, so you could handle it at that time. Your other options are to require that it is either the first or the last option and handle it by itself separately.
至于你的文件名选项,你会把它作为'?'从getopt_long()调用,所以你可以在那时处理它。您的其他选择是要求它是第一个或最后一个选项并单独处理它。
#2
5
If you use the popt library, you will be able to create something smart as you did in your pseudo-code:
如果您使用popt库,您将能够像在伪代码中一样创建智能:
#include <stdio.h>
#include "popt.h"
struct _field {
char *title;
char *artist;
/* etc */
} field;
field.title = NULL;
field.artist = NULL;
/* HERE IS WHAT YOU WANTED IN YOUR PSEUDO-CODE */
struct poptOption optionsTable[] = {
{"title", 't', POPT_ARG_STRING, &field.title, 't'
"set the 'title' of the album" },
{"artist", 'a', POPT_ARG_STRING, &field.artist, 'a'
"set the 'artist' of the album" },
POPT_AUTOHELP
POPT_TABLEEND
};
poptContext optCon = poptGetContext(NULL, argc, argv, optionsTable, 0);
poptSetOtherOptionHelp(optCon, "[OPTIONS]");
char c;
while ((c = poptGetNextOpt(optCon)) >= 0) {
switch (c) {
case 't':
/* do extra stuff only if you need */
break;
case 'a':
/* do extra stuff only if you need */
break;
default:
poptPrintUsage(optCon, stderr, 0);
exit(1);
}
}
if (field.title) printf("\nTitle is [%s]", field.title);
if (field.artist) printf("\nArtist is [%s]", field.artist)
Be smart than getopt ;)
比getopt聪明;)
#1
23
First off, you probably don't want 0
for the has_arg
field - it must be one of no_argument
, required_arguemnt
, or optional_argument
. In your case, all of them are going to be required_argument
. Besides that, you're not using the flag
field correctly - it has to be an integer pointer. If the corresponding flag is set, getopt_long()
will fill it in with the integer you passed in via the val
field. I don't think you need this feature at all. Here's a better (shortened) example for your case:
首先,你可能不希望has_arg字段为0 - 它必须是no_argument,required_arguemnt或optional_argument之一。在您的情况下,所有这些都将是required_argument。除此之外,你没有正确使用标志字段 - 它必须是一个整数指针。如果设置了相应的标志,getopt_long()将使用通过val字段传入的整数填充它。我认为你根本不需要这个功能。这是一个更好(缩短)的例子:
static struct option long_options[] =
{
{"title", required_argument, NULL, 't'},
{"artist", required_argument, NULL, 'a'},
{NULL, 0, NULL, 0}
};
Then later, you can use it appropriately (straight from the manpage, I added some comments):
然后,您可以适当地使用它(直接从联机帮助页,我添加了一些注释):
// loop over all of the options
while ((ch = getopt_long(argc, argv, "t:a:", long_options, NULL)) != -1)
{
// check to see if a single character or long option came through
switch (ch)
{
// short option 't'
case 't':
field.title = optarg; // or copy it if you want to
break;
// short option 'a'
case 'a':
field.artist = optarg; // or copy it if you want to
break;
}
}
You can extend for your other fields as necessary (and add some error handling, please!). Note - if you want to use -title
and -artist
like you have in your example, you'll need to use getopt_long_only()
, which doesn't have short options.
您可以根据需要扩展其他字段(并添加一些错误处理,请!)。注意 - 如果你想在你的例子中使用-title和-artist,你需要使用getopt_long_only(),它没有短选项。
As to your filename
option, you'll get that out as a '?'
from the getopt_long()
call, so you could handle it at that time. Your other options are to require that it is either the first or the last option and handle it by itself separately.
至于你的文件名选项,你会把它作为'?'从getopt_long()调用,所以你可以在那时处理它。您的其他选择是要求它是第一个或最后一个选项并单独处理它。
#2
5
If you use the popt library, you will be able to create something smart as you did in your pseudo-code:
如果您使用popt库,您将能够像在伪代码中一样创建智能:
#include <stdio.h>
#include "popt.h"
struct _field {
char *title;
char *artist;
/* etc */
} field;
field.title = NULL;
field.artist = NULL;
/* HERE IS WHAT YOU WANTED IN YOUR PSEUDO-CODE */
struct poptOption optionsTable[] = {
{"title", 't', POPT_ARG_STRING, &field.title, 't'
"set the 'title' of the album" },
{"artist", 'a', POPT_ARG_STRING, &field.artist, 'a'
"set the 'artist' of the album" },
POPT_AUTOHELP
POPT_TABLEEND
};
poptContext optCon = poptGetContext(NULL, argc, argv, optionsTable, 0);
poptSetOtherOptionHelp(optCon, "[OPTIONS]");
char c;
while ((c = poptGetNextOpt(optCon)) >= 0) {
switch (c) {
case 't':
/* do extra stuff only if you need */
break;
case 'a':
/* do extra stuff only if you need */
break;
default:
poptPrintUsage(optCon, stderr, 0);
exit(1);
}
}
if (field.title) printf("\nTitle is [%s]", field.title);
if (field.artist) printf("\nArtist is [%s]", field.artist)
Be smart than getopt ;)
比getopt聪明;)