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65 lines
1.2 KiB
C
65 lines
1.2 KiB
C
#include <stdio.h>
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#include <printf.h>
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#include <stdarg.h>
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/*@group*/
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typedef struct
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{
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char *name;
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} Widget;
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/*@end group*/
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int
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print_widget (FILE *stream, const struct printf_info *info, va_list *app)
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{
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Widget *w;
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char *buffer;
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int len;
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/* Format the output into a string. */
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w = va_arg (*app, Widget *);
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len = asprintf (&buffer, "<Widget %p: %s>", w, w->name);
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if (len == -1)
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return -1;
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/* Pad to the minimum field width and print to the stream. */
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len = fprintf (stream, "%*s",
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(info->left ? - info->width : info->width),
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buffer);
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/* Clean up and return. */
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free (buffer);
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return len;
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}
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int
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print_widget_arginfo (const struct printf_info *info, size_t n,
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int *argtypes)
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{
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/* We always take exactly one argument and this is a pointer to the
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structure.. */
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if (n > 0)
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argtypes[0] = PA_POINTER;
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return 1;
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}
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int
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main (void)
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{
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/* Make a widget to print. */
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Widget mywidget;
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mywidget.name = "mywidget";
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/* Register the print function for widgets. */
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register_printf_function ('W', print_widget, print_widget_arginfo);
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/* Now print the widget. */
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printf ("|%W|\n", &mywidget);
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printf ("|%35W|\n", &mywidget);
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printf ("|%-35W|\n", &mywidget);
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return 0;
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}
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