19.2.2.4 Restrictions on Examining Pathname Components

The space of possible objects that a conforming program must be prepared to read[1] as the value of a pathname component is substantially larger than the space of possible objects that a conforming program is permitted to write[1] into such a component.

While the values discussed in the subsections of this section, in Section 19.2.2.2 (Special Pathname Component Values), and in Section 19.2.2.3 (Restrictions on Wildcard Pathnames) apply to values that might be seen when reading the component values, substantially more restrictive rules apply to constructing pathnames; see Section 19.2.2.5 (Restrictions on Constructing Pathnames).

When examining pathname components, conforming programs should be aware of the following restrictions.

19.2.2.4.1 Restrictions on Examining a Pathname Host Component

19.2.2.4.2 Restrictions on Examining a Pathname Device Component

19.2.2.4.3 Restrictions on Examining a Pathname Directory Component

19.2.2.4.4 Restrictions on Examining a Pathname Name Component

19.2.2.4.5 Restrictions on Examining a Pathname Type Component

19.2.2.4.6 Restrictions on Examining a Pathname Version Component

19.2.3 Merging Pathnames