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| Beide Seiten der vorigen Revision Vorhergehende Überarbeitung Nächste Überarbeitung | Vorhergehende Überarbeitung | ||
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becki:linux:c [2017-01-20 10:45] becki |
becki:linux:c [2017-12-07 14:19] (aktuell) becki [Definition of constant Strings] |
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| Zeile 90: | Zeile 90: | ||
| while (fgets(lin, MAX_LINE_LEN, stdin)) {/* do some thing */} | while (fgets(lin, MAX_LINE_LEN, stdin)) {/* do some thing */} | ||
| </code> | </code> | ||
| + | |||
| + | <note tip>If input line lenght is unknown, use ''getline()'' instead of ''fgets()''! | ||
| + | (See ''freesigs/io_modbus'')</note> | ||
| ''scanf'' can also be used for reading from ''stdin''. | ''scanf'' can also be used for reading from ''stdin''. | ||
| Zeile 108: | Zeile 111: | ||
| </code> | </code> | ||
| - | Writing to ''stderr'' is unbuffered, writing to ''stdout'' is buffered ((CARM p.351)) => Always use ''stderr'' for debugging messages ((RRUSP p.68)) | + | Writing to ''stderr'' is unbuffered, writing to ''stdout'' is buffered ((CARM p.351)) |
| + | ⇒ Always use ''stderr'' for debugging messages ((RRUSP p.68)) | ||
| ===== Constants ====== | ===== Constants ====== | ||
| Zeile 217: | Zeile 221: | ||
| [static] const char *mystring= "String" // false, needs 6 Bytes + Pointer | [static] const char *mystring= "String" // false, needs 6 Bytes + Pointer | ||
| </code> | </code> | ||
| + | |||
| * ''static'' to limit the scope for global strings. Not necessary inside a code block. | * ''static'' to limit the scope for global strings. Not necessary inside a code block. | ||
| * see also [[http://www.dclc-faq.de/kap2.htm|de.comp.lang.c FAQ]] -> Frage 2.2 / K&R p.101 / Carm p.124 | * see also [[http://www.dclc-faq.de/kap2.htm|de.comp.lang.c FAQ]] -> Frage 2.2 / K&R p.101 / Carm p.124 | ||
| + | * //Writable// strings must be declared as array (eg ''char a[]= "aff";'') not as pointer. See Carm p 32 | ||
| === Detailed Description == | === Detailed Description == | ||
becki/linux/c.1484909147.txt.gz · Zuletzt geändert: 2017-01-20 10:45 von becki
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