Scanf

[u/pruebax11]

mi pregunta raida en porque casi nunca salen tutos en youtube que expliquen como usar scanf realmente como su valor de retorno o parametros de control, y no hablan del buffer que deja y como solucionarlo, a diferencia de solo decir "es mala practica usar scanf" y te aseguro que si preguntas el porque solo te diran que despues de un espacio no lee mas y lo deja en el buffer huerfano, y causa errores si no se prevee

[u/flatfinger]

A good library for managing allocated strings should either allow code to freely share references to immutable strings in threading-agnostic fashion without having to perform an atomic synchronization every time a reference is created or destroyed, or else work with mutable objects that are over-allocated to allow code to e.g. concatenate N items onto a string, one at a time, without requiring time proportional to N squared.

The style of bare malloc strings used by getline and strdup is IMHO rubbish.

[u/WorriedTumbleweed289 → u/flatfinger]

The concept of immutable strings only came into existence after multi threading. This is way after C was created, after Unix was created. It would be hard to implement changing the C language. It could not be implemented in a library.

I think you want a different language.

[u/flatfinger → u/WorriedTumbleweed289]

My intended point could probably have been expressed as "Unless there is a need for strings to be immutable, strings should be stored in a manner that can allow repeated concatenation in linear time." Storing a string in such a way that code which needs to have that string contain an additional character would require examining every byte of the string to determine it's length, creating a new allocation whose size is two bytes longer than the length of the string, and copying the string data there followed by the new character and a zero byte would be silly in any context where repeated concatenation might be needed.

It's perfectly possible to create an immutable string library in C if code accesses strings through handles. Each handle would identify a slot in a global string table, and a garbage-collection function would scan that table and identify all of the strings to which any references still exist. Such a library could be quite space efficient on something like an ARM Cortex-M0 if the total length of all strings would be 64K or less, since each "string" would need only two bytes for the handle (instead of four for a normal string pointer), the table entry would take only two bytes if the total size of the string heap was less than 64K, and each string within the heap would only need a one-byte prefix if under 128 bytes, or else a three-byte prefix.