HP-UX Reference (11i v1 05/09) - 3 Library Functions N-Z (vol 7)

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scanf(3S) scanf(3S)

25 54.32E-1 thompson

assigns to n the value 3,toi the value

25,tox the value 5.432, and name contains thompson\0. Or:

int i; float x; char name[50];

(void) scanf("%2d%f%*d %[0-9]", &i, &x, name);

with input:

56789 0123 56a72

assigns 56 to i, 789.0 to x, skips

0123, and places the string 56\0 in name. The next call to

getchar() (see getc(3S)) returns a.

For another example, to create a language-independent date scanning routine, use:

char month[20]; int day, year;

(void) scanf(format, month, &day, &year);

For American usage, format would point to a string:

%1$s %2$d %3$d

The input:

July 3 1986

would assign July to month, 3 to day and 1986 to year.

For German usage, format would point to a string:

%2$d %1$s %3$d

The input:

3 Juli 1986

would assign Juli to month, 3 to day and 1986 to year.

The success of literal matches and suppressed assignments can be determined with the %n conversion

speciﬁcation. Here is an example that checks the success of literal matches:

int i, n1, n2, n3, n4;

n1 = n2 = n3 = n4 = -1;

scanf("%nBEGIN%n %d %nEND%n", &n1, &n2, &i, &n3, &n4);

if (n2 - n1 == 5) puts( "matched BEGIN");

if (n4 - n3 == 3) puts( "matched END");

Here is an example that checks the success of suppressed assignments:

int i, n1, n2;

n1 = n2 = -1;

scanf( "%d %n%*s%n", &i, &n1, &n2);

if (n2 > n1)

printf("successful assignment suppression of %d chars\n", n2-n1);

APPLICATION USAGE

After scanf() or fscanf() is applied to a stream, the stream becomes byte-oriented (see orienta-

tion(5)).

WARNINGS

Trailing white space (including a newline) is left unread unless matched in the control string.

Truncation of multi-byte characters may occur if a ﬁeld width is used with the conversion character.

AUTHOR

scanf() was developed by AT&T and HP.