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54 lines
1.4 KiB
Markdown
54 lines
1.4 KiB
Markdown
## Introduction
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The `arg` module is primarily designed for scenarios that involve variable numbers of arguments, allowing you to retrieve the count of those arguments and access specific positional arguments.
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## Interface
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### Functions
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```c
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#define ARG_MAX // Maximum number of supported variable arguments
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#define ARGC(...) // Current number of variable arguments, does not support distinguishing empty arguments
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#define ARGC0(...) // Current number of variable arguments, supports distinguishing empty arguments but requires more compile-time space; use as needed
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#define ARGS(x, ...) // Retrieve the argument at a specified position
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```
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In usage, you only need to focus on the macro definitions above; the rest can be ignored.
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Example usage:
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```c
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static void test(void)
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{
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printf("ARG_MAX %d\r\n", ARG_MAX);
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printf("ARGC %d\r\n", ARGC());
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printf("ARGC %d\r\n", ARGC(A));
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printf("ARGC %d\r\n", ARGC(A, B));
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printf("ARGC %d\r\n", ARGC(A, B, C));
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printf("ARGC %d\r\n", ARGC0());
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printf("ARGC %d\r\n", ARGC0(A));
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printf("ARGC %d\r\n", ARGC0(A, B));
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printf("ARGC %d\r\n", ARGC0(A, B, C));
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printf("ARGS %s\r\n", ARGS(0, "arg0", "arg1", "arg2"));
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printf("ARGS %s\r\n", ARGS(1, "arg0", "arg1", "arg2"));
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printf("ARGS %s\r\n", ARGS(2, "arg0", "arg1", "arg2"));
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}
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```
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Results:
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```
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ARG_MAX 124
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ARGC 1
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ARGC 1
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ARGC 2
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ARGC 3
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ARGC 0
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ARGC 1
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ARGC 2
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ARGC 3
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ARGS arg0
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ARGS arg1
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ARGS arg2
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```
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