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/*
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* routines used to manipulate the environment block
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* Copyright (C) 2021, Mateusz Viste
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*/
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#ifndef ENV_H
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#define ENV_H
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/* looks for varname in environment block and returns a far ptr to it if
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* found, NULL otherwise. varname MUST be in upper-case and MUST be terminated
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* by either a = sign or a NULL terminator */
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char far *env_lookup(unsigned short env_seg, const char *varname);
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/* returns the size, in bytes, of the allocated environment block */
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unsigned short env_allocsz(unsigned short env_seg);
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/* remove a variable from environment, if present. returns 0 on success, non-zero if variable not found */
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int env_dropvar(unsigned short env_seg, const char *varname);
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#define ENV_SUCCESS 0
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#define ENV_NOTENOM -1
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#define ENV_INVSYNT -2
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/* Writes a variable to environment block. The variable must in the form
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* "varname=value". If variable is already present in the environment block,
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* then the value will be updated. If the new value is empty, then the
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* existing variable (if any) is removed.
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*
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* This function returns:
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* ENV_SUCCESS = success
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* ENV_NOTENOM = not enough available space in memory block
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* ENV_INVSYNT = invalid syntax
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*/
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int env_setvar(unsigned short env_seg, const char *v);
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#endif
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