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/*
* Linux DTrace
* Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
#!/usr/sbin/dtrace -s
/*
* SYNOPSIS
* sudo ./005intro-strings.d
*
* DESCRIPTION
* But D does differ from C when it comes to strings.
* The D language has a built-in string data type.
*/
/*
* Strings are stored in arrays of fixed length. The
* default length 256 can be overridden with a D option.
*/
#pragma D option strsize=12
/* string variables can be declared explicitly */
string exp;
string s1, s2, s3, s4;
char carray[32];
BEGIN
{
/* strings are truncated, if necessary, per strsize */
printf("%s\n", "abcdefghijklmnopqrstuvwxyz");
/* string variables can be declared implicitly */
imp = "abcdefghijklmnopqrstuvwxyz";
printf("%d chars, string %s\n", sizeof(imp), imp);
/* operators can be used to order strings lexically (akin to strcmp) */
exp = "zyxwvutsrqponmlkjihgfedcba";
printf("%s is %s than %s\n", imp, imp < exp ? "less" : "greater", exp);
/* set up NULL-terminated char array for some illustration purposes */
carray[ 0] = 'A'; carray[ 1] = 'B'; carray[ 2] = 'C'; carray[ 3] = 'D';
carray[ 4] = 'E'; carray[ 5] = 'F'; carray[ 6] = 'G'; carray[ 7] = 'H';
carray[ 8] = 'I'; carray[ 9] = 'J'; carray[10] = 'K'; carray[11] = 'L';
carray[12] = 'M'; carray[13] = 'N'; carray[14] = 'O'; carray[15] = 'P';
carray[16] = 'Q'; carray[17] = 'R'; carray[18] = 'S'; carray[19] = 'T';
carray[20] = 'U'; carray[21] = 'V'; carray[22] = 'W'; carray[23] = 'X';
carray[24] = 'Y'; carray[25] = 'Z'; carray[26] = '\0';
/* char pointers can be turned into strings */
s1 = (string) carray; /* type casting */
s2 = stringof carray; /* stringof operator */
/* char pointers can be promoted automatically to strings */
s3 = carray;
s4 = strchr(carray, 'B');
/*
* Note that in the above assignments, we did not simply set
* a char* to some existing string buffer. Rather, contents
* are copied "by-value" to the destination string buffer.
* E.g., if the source buffer is modified, the output strings
* nevertheless all stay the same.
*/
carray[2] = '\0';
printf("%s %s %s %s %s\n", s1, s2, s3, s4, carray);
exit(0);
}
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