48 lines
893 B
Markdown
48 lines
893 B
Markdown
# stdarg.h
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`stdarg.h`定义于函数的可变参数相关的一些方法。
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- va_list 类型
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- va_start()
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- va_arg()：获取当前参数
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- va_end()。
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va_copy()：it makes a copy of your va_list variable in the exact same state.
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va_copy() can be useful if you need to scan ahead through the arguments but need to also remember your current place.
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接受可变函数作为参数的一些方法。
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- vprintf()
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- vfprintf()
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- vsprintf()
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- vsnprintf()
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```c
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#include <stdio.h>
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#include <stdarg.h>
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int my_printf(int serial, const char *format, ...)
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{
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va_list va;
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// Do my custom work
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printf("The serial number is: %d\n", serial);
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// Then pass the rest off to vprintf()
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va_start(va, format);
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int rv = vprintf(format, va);
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va_end(va);
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return rv;
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}
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int main(void)
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{
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int x = 10;
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float y = 3.2;
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my_printf(3490, "x is %d, y is %f\n", x, y);
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}
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```
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